Prepare brownie mix according to package instructions. Line a 13"x9" baking pan with aluminum foil, leaving several inches on sides for handles. Spray bottom of foil with non-stick vegetable spray; spread batter into pan. Bake at 350 degrees for 24 to 26 minutes; let cool. Lift brownies from pan; remove foil. Use a 3-inch heart-shaped cookie cutter to cut brownies. In a microwave-safe bowl, melt white baking chocolate and whipping cream for one to 2 minutes, stirring until chocolate is melted; refrigerate 30 minutes. Stir frosting and cherries into chilled chocolate mixture; spread over brownies. In a microwave-safe bowl, melt chocolate chips and butter for one to 2 minutes, stirring until smooth. Transfer to a plastic zipping bag, snip off a tip and drizzle over brownies. Garnish with sprinkles.